Methods and Systems for Treatment of Occipital Neuralgia

ABSTRACT

A system for alleviating occipital neuralgia. The system has a needle probe having at least one needle. The at least one needle has a proximal end, a distal end, and a needle lumen therebetween, the needle configured for insertion proximate to a location of the occipital nerve. A cooling fluid supply lumen extends distally within the needle lumen to a distal portion of the needle lumen. A cooling fluid source is coupled to the cooling fluid supply lumen to direct cooling fluid flow into the needle lumen. A controller that has at least one processor configured implements an occipital neuralgia treatment algorithm for controlling the cooling fluid source so that liquid from the cooling flow vaporizes within the needle lumen to provide a treatment phase to location of the occipital nerve such that the occipital neuralgia is mitigated.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.15/457,642 filed Mar. 13, 2017; which is a Divisional of U.S.application Ser. No. 14/218,901 filed Mar. 18, 2014, now U.S. patentSer. No. 10/016,229 issued Jul. 10, 2018; which claims benefit of U.S.Provisional Patent Application No. 61/800,478, filed Mar. 15, 2013; theentire contents of which are incorporated herein by reference in theirentirety for all purposes.

BACKGROUND OF THE INVENTION

Occipital neuralgia s a medical condition characterized by chronic painin the upper neck, back of the head and behind the eyes. Often,occipital nerualgia causes a distinct type of headache characterized bypiercing, throbbing, or electric-shock-like chronic pain in the upperneck, back of the head, and behind the ears, usually on one side of thehead. Typically, the pain of occipital neuralgia begins in the neck andthen spreads upwards. Some individuals will also experience pain in thescalp, forehead, and behind the eyes. Their scalp may also be tender tothe touch, and their eyes especially sensitive to light. The location ofpain is related to the areas supplied by the greater and lesseroccipital nerves, which run from the area where the spinal column meetsthe neck, up to the scalp at the back of the head. The pain is caused byirritation or injury to the nerves, which can be the result of trauma tothe back of the head, pinching of the nerves by overly tight neckmuscles, compression of the nerve as it leaves the spine due toosteoarthritis, or tumors or other types of lesions in the neck.Localized inflammation or infection, gout, diabetes, blood vesselinflammation (vasculitis), and frequent lengthy periods of keeping thehead in a downward and forward position are also associated withoccipital neuralgia. In many cases, however, no cause can be found. Apositive response (relief from pain) after an anesthetic nerve blockwill confirm the diagnosis.

Treatment is generally symptomatic and includes massage and rest. Insome cases, antidepressants may be used when the pain is particularlysevere. Other treatments may include local nerve blocks and injectionsof steroids directly into the affected area.

Occipital neuralgia is not a life-threatening condition. Manyindividuals will improve with therapy involving heat, rest,anti-inflammatory medications, and muscle relaxants. Recovery is usuallycomplete after the bout of pain has ended and the nerve damage repairedor lessened.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the invention are related to a system for alleviatingoccipital neuralgia. The system can include a needle probe having atleast one needle. The at least one needle having a proximal end, adistal end, and a needle lumen therebetween, the needle configured forinsertion proximate to a location of the occipital nerve. A coolingfluid supply lumen can extend distally within the needle lumen to adistal portion of the needle lumen. A cooling fluid source can becoupled to the cooling fluid supply lumen to direct cooling fluid flowinto the needle lumen. The system can include a controller having atleast one processor configured to implement an occipital neuralgiatreatment algorithm for controlling the cooling fluid source so thatliquid from the cooling flow vaporizes within the needle lumen toprovide a treatment cycle to a location of the occipital nerve such thatthe occipital neuralgia is mitigated.

Embodiments of the invention are also related to a method foralleviating occipital neuralgia. In the method, a distal end of acryogenic cooling needle probe is positioned proximal to a location ofthe occipital nerve, the needle probe having at least one needle with alumen. A treatment is delivered to the target tissue with the cryogeniccooling needle. The treatment includes a cooling phase where coolingfluid flows into the needle lumen so that liquid from the cooling flowvaporizes within the needle lumen to provide cooling to the nerve suchthat the occipital neuralgia is mitigated.

In many embodiments, a heating element coupled with a proximal portionof the needle, and the heating element can be to deliver heating phasesto the skin of the patient. The processor can be configured to controlthe cooling fluid flow and the heating element in response to operatorinput, the processor configured to provide the treatment cycle inresponse to the operator input, the treatment cycle comprising at leastone heating phase and one cooling phase.

In many embodiments, the location of the occipital nerve comprises thegreater occipital nerve (GON).

In many embodiments, the at least one needle is configured to access theGON.

In many embodiments, the needle probe comprises at pair of needlesspaced apart 3-7 mm to flank the GON, each needle being greater than 6mm in length.

In many embodiments, the location of the occipital nerve comprises thelower occipital nerve (LON).

In many embodiments, the at least one needle is configured to access theLON.

In many embodiments, the needle probe comprises at pair of needlesspaced apart 3-7 mm to flank the LON, each needle being greater than 6mm in length.

In many embodiments, the occipital neuralgia treatment algorithm isconfigured to cause the needle probe to generate a cryozone having avolume of 65-125 mm³.

In many embodiments, one or a combination of transcutaneous electricalnerve stimulation, percutaneous electrical nerve stimulation, andultrasound is used to locate the motor nerve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a self-contained subdermal cryogenicremodeling probe and system, according to some embodiments of theinvention;

FIG. 1B is a partially transparent perspective view of theself-contained probe of FIG. 1A, showing internal components of thecryogenic remodeling system and schematically illustrating replacementtreatment needles for use with the disposable probe according to someembodiments of the invention;

FIG. 2A schematically illustrates exemplary components that may beincluded in the treatment system;

FIG. 2B is a cross-sectional view of the system of FIG. 1A, according tosome embodiments of the invention;

FIGS. 2C and 2D are cross-sectional views showing exemplary operationalmodes of the system of FIG. 2B;

FIGS. 3A-3B illustrate exemplary embodiment of a needle probe, accordingto some embodiments of the invention;

FIGS. 3C-3D illustrate an exemplary embodiment of a detachable probetip, according to some embodiments of the invention.

FIG. 4A is a flow chart illustrating an exemplary algorithm for heatingthe needle probe of FIG. 3A, according to some embodiment of theinvention;

FIG. 4B is a flow chart schematically illustrating an exemplary methodfor treatment using the disposable cryogenic probe and system of FIGS.1A and 1B, according to some embodiments of the invention;

FIG. 5 shows an illustration of the greater occipital nerve;

FIG. 6 shows a greater occipital nerve treatments sites, according tosome embodiment of the invention;

FIG. 7 shows the location of the lesser occipital nerve;

FIG. 8 shows a schematic illustration of the courses of the greater andlesser occipital nerves;

FIG. 9 shows a schematic illustration of GON and LON treatmentlocations, according to some embodiment of the invention;

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides improved medical devices, systems, andmethods. Embodiments of the invention may facilitate remodeling oftarget tissues disposed at and below the skin, optionally treatoccipital neuralgia by remodeling tissue of a occipital nerve.Embodiments of the invention may utilize a handheld refrigeration systemthat can use a commercially available cartridge of fluid refrigerant.Refrigerants well suited for use in handheld refrigeration systems mayinclude nitrous oxide and carbon dioxide. These can achieve temperaturesapproaching −90° C.

Occipital nerves and associated tissues may be temporarily immobilizedusing moderately cold temperatures of 10° C. to −5° C. withoutpermanently disabling the tissue structures. Using an approach similarto that employed for identifying structures associated with atrialfibrillation, a needle probe or other treatment device can be used toidentify a target tissue structure in a diagnostic mode with thesemoderate temperatures, and the same probe (or a different probe) canalso be used to provide a longer term or permanent treatment, optionallyby ablating the target tissue zone and/or inducing apoptosis attemperatures from about −5° C. to about −50° C. In some embodiments,apoptosis may be induced using treatment temperatures from about −1° C.to about −15° C., or from about −1° C. to about −19° C., optionally soas to provide a longer lasting treatment that limits or avoidsinflammation and mobilization of skeletal muscle satellite repair cells.In some embodiments, axonotmesis with Wallerian degeneration of a nerveis desired, which may be induced using treatment temperatures from about−20° C. to about −100° C. Hence, the duration of the treatment efficacyof such subdermal cryogenic treatments may be selected and controlled,with colder temperatures, longer treatment times, and/or larger volumesor selected patterns of target tissue determining the longevity of thetreatment. Additional description of cryogenic cooling methods anddevices may be found in commonly assigned U.S. Pat. No. 7,713,266 (Atty.Docket No. 000110US) entitled “Subdermal Cryogenic Remodeling of Muscle,Nerves, Connective Tissue, and/or Adipose Tissue (Fat)”, U.S. Pat. No.7,850,683 (Atty. Docket No. 000120US) entitled “Subdermal CryogenicRemodeling of Muscles, Nerves, Connective Tissue, and/or Adipose Tissue(Fat)”, U.S. patent application Ser. No. 13/325,004 (Atty. Docket No.002510US) entitled “Method for Reducing Hyperdynamic Facial Wrinkles”,and U.S. Pub. No. 2009/0248001 (Atty. Docket No. 000800US) entitled“Pain Management Using Cryogenic Remodeling,” the full disclosures ofwhich are each incorporated by reference herein.

Cryogenic Systems for Treating Occipital Neuralgia

Referring now to FIGS. 1A and 1B, a system for cryogenic remodeling herecomprises a self-contained probe handpiece generally having a proximalend 12 and a distal end 14. A handpiece body or housing 16 has a sizeand ergonomic shape suitable for being grasped and supported in asurgeon's hand or other system operator. As can be seen most clearly inFIG. 1B, a cryogenic cooling fluid supply 18, a supply valve 32 andelectrical power source 20 are found within housing 16, along with acircuit 22 having a processor for controlling cooling applied byself-contained system 10 in response to actuation of an input 24.Alternatively, electrical power can be applied through a cord from aremote power source. Power source 20 also supplies power to heaterelement 44 in order to heat the proximal region of probe 26 which maythereby help to prevent unwanted skin damage, and a temperature sensor48 adjacent the proximal region of probe 26 helps monitor probetemperature. Additional details on the heater 44 and temperature sensor48 are described in greater detail below. When actuated, supply valve 32controls the flow of cryogenic cooling fluid from fluid supply 18. Someembodiments may, at least in part, be manually activated, such asthrough the use of a manual supply valve and/or the like, so thatprocessors, electrical power supplies, and the like may not be required.

Extending distally from distal end 14 of housing 16 may be atissue-penetrating cryogenic cooling probe 26. Probe 26 is thermallycoupled to a cooling fluid path extending from cooling fluid source 18,with the exemplary probe comprising a tubular body receiving at least aportion of the cooling fluid from the cooling fluid source therein. Theexemplary probe 26 may comprise a 30 g needle having a sharpened distalend that is axially sealed. Probe 26 may have an axial length betweendistal end 14 of housing 16 and the distal end of the needle of betweenabout 0.5 mm and 15 cm, preferably having a length from about 3 mm toabout 10 mm. Such needles may comprise a stainless steel tube with aninner diameter of about 0.006 inches and an outer diameter of about0.012 inches, while alternative probes may comprise structures havingouter diameters (or other lateral cross-sectional dimensions) from about0.006 inches to about 0.100 inches. Generally, needle probe 26 maycomprise a 16 g or smaller size needle, often comprising a 20 g needleor smaller, typically comprising a 25, 26, 27, 28, 29, or 30 g orsmaller needle.

In some embodiments, probe 26 may comprise two or more needles arrangedin a linear array, such as those disclosed in previously incorporatedU.S. Pat. No. 7,850,683. Another exemplary embodiment of a probe havingmultiple needle probe configurations allow the cryogenic treatment to beapplied to a larger or more specific treatment area. Other needleconfigurations that facilitate controlling the depth of needlepenetration and insulated needle embodiments are disclosed in commonlyassigned U.S. Patent Publication No. 2008/0200910 (Atty. Docket No.000500US) entitled “Replaceable and/or Easily Removable Needle Systemsfor Dermal and Transdermal Cryogenic Remodeling,” the entire content ofwhich is incorporated herein by reference. Multiple needle arrays mayalso be arrayed in alternative configurations such as a triangular orsquare array.

Arrays may be designed to treat a particular region of tissue, or toprovide a uniform treatment within a particular region, or both. In someembodiments needle 26 may be releasably coupled with body 16 so that itmay be replaced after use with a sharper needle (as indicated by thedotted line) or with a needle having a different configuration. Inexemplary embodiments, the needle may be threaded into the body, pressfit into an aperture in the body or have a quick disconnect such as adetent mechanism for engaging the needle with the body. A quickdisconnect with a check valve may be advantageous since it may permitdecoupling of the needle from the body at any time without excessivecoolant discharge. This can be a useful safety feature in the event thatthe device fails in operation (e.g. valve failure), allowing an operatorto disengage the needle and device from a patient's tissue withoutexposing the patient to coolant as the system depressurizes. Thisfeature may also be advantageous because it allows an operator to easilyexchange a dull needle with a sharp needle in the middle of a treatment.One of skill in the art will appreciate that other coupling mechanismsmay be used.

Addressing some of the components within housing 16, the exemplarycooling fluid supply 18 may comprise a canister, sometimes referred toherein as a cartridge, containing a liquid under pressure, with theliquid preferably having a boiling temperature of less than 37° C. atone atmosphere of pressure. When the fluid is thermally coupled to thetissue-penetrating probe 26, and the probe is positioned within thepatient so that an outer surface of the probe is adjacent to a targettissue, the heat from the target tissue evaporates at least a portion ofthe liquid and the enthalpy of vaporization cools the target tissue. Asupply valve 32 may be disposed along the cooling fluid flow pathbetween canister 18 and probe 26, or along the cooling fluid path afterthe probe so as to limit coolant flow thereby regulating thetemperature, treatment time, rate of temperature change, or othercooling characteristics. The valve will often be powered electricallyvia power source 20, per the direction of processor 22, but may at leastin part be manually powered. The exemplary power source 20 comprises arechargeable or single-use battery. Additional details about valve 32are disclosed below and further disclosure on the power source 20 may befound in commonly assigned Int'l Pub. No. WO 2010/075438 (Atty. DocketNo. 002310PC) entitled “Integrated Cryosurgical Probe Package with FluidReservoir and Limited Electrical Power Source,” the entire contents ofwhich are incorporated herein by reference.

The exemplary cooling fluid supply 18 may comprise a single-usecanister. Advantageously, the canister and cooling fluid therein may bestored and/or used at (or even above) room temperature. The canister mayhave a frangible seal or may be refillable, with the exemplary canistercontaining liquid nitrous oxide, N₂O. A variety of alternative coolingfluids might also be used, with exemplary cooling fluids includingfluorocarbon refrigerants and/or carbon dioxide. The quantity of coolingfluid contained by canister 18 will typically be sufficient to treat atleast a significant region of a patient, but will often be less thansufficient to treat two or more patients. An exemplary liquid N₂Ocanister might contain, for example, a quantity in a range from about 1gram to about 40 grams of liquid, more preferably from about 1 gram toabout 35 grams of liquid, and even more preferably from about 7 grams toabout 30 grams of liquid.

Processor 22 will typically comprise a programmable electronicmicroprocessor embodying machine readable computer code or programminginstructions for implementing one or more of the treatment methodsdescribed herein. The microprocessor will typically include or becoupled to a memory (such as a non-volatile memory, a flash memory, aread-only memory (“ROM”), a random access memory (“RAM”), or the like)storing the computer code and data to be used thereby, and/or arecording media (including a magnetic recording media such as a harddisk, a floppy disk, or the like; or an optical recording media such asa CD or DVD) may be provided. Suitable interface devices (such asdigital-to-analog or analog-to-digital converters, or the like) andinput/output devices (such as USB or serial I/O ports, wirelesscommunication cards, graphical display cards, and the like) may also beprovided. A wide variety of commercially available or specializedprocessor structures may be used in different embodiments, and suitableprocessors may make use of a wide variety of combinations of hardwareand/or hardware/software combinations. For example, processor 22 may beintegrated on a single processor board and may run a single program ormay make use of a plurality of boards running a number of differentprogram modules in a wide variety of alternative distributed dataprocessing or code architectures.

Referring now to FIG. 2A, schematic 11 shows a simplified diagram ofcryogenic cooling fluid flow and control. The flow of cryogenic coolingfluid from fluid supply 18 may be controlled by a supply valve 32.Supply valve 32 may comprise an electrically actuated solenoid valve, amotor actuated valve or the like operating in response to controlsignals from controller 22, and/or may comprise a manual valve.Exemplary supply valves may comprise structures suitable for on/offvalve operation, and may provide venting of the fluid source and/or thecooling fluid path downstream of the valve when cooling flow is haltedso as to limit residual cryogenic fluid vaporization and cooling.Additionally, the valve may be actuated by the controller in order tomodulate coolant flow to provide high rates of cooling in some instanceswhere it is desirable to promote necrosis of tissue such as in malignantlesions and the like or slow cooling which promotes ice formationbetween cells rather than within cells when necrosis is not desired.More complex flow modulating valve structures might also be used inother embodiments. For example, other applicable valve embodiments aredisclosed in previously incorporated U.S. Pub. No. 2008/0200910.

Still referring to FIG. 2A, an optional heater (not illustrated) may beused to heat cooling fluid supply 18 so that heated cooling fluid flowsthrough valve 32 and through a lumen 34 of a cooling fluid supply tube36. In some embodiments a safety mechanism can be included so that thecooling supply is not overheated. Examples of such embodiments aredisclosed in commonly assigned International Publication No. WO2010075438, the entirety of which is incorporated by reference herein.

Supply tube 36 is, at least in part, disposed within a lumen 38 ofneedle 26, with the supply tube extending distally from a proximal end40 of the needle toward a distal end 42. The exemplary supply tube 36comprises a fused silica tubular structure (not illustrated) having apolymer coating and extending in cantilever into the needle lumen 38.Supply tube 36 may have an inner lumen with an effective inner diameterof less than about 200 μm, the inner diameter often being less thanabout 100 μm, and typically being less than about 40 μm. Exemplaryembodiments of supply tube 36 have inner lumens of between about 15 and50 μm, such as about 30 μm. An outer diameter or size of supply tube 36will typically be less than about 1000 μm, often being less than about800 μm, with exemplary embodiments being between about 60 and 150 μm,such as about 90 μm or 105 μm. The tolerance of the inner lumen diameterof supply tubing 36 will preferably be relatively tight, typically beingabout +/−10 μm or tighter, often being +/−5 μm or tighter, and ideallybeing +/−3 μm or tighter, as the small diameter supply tube may providethe majority of (or even substantially all of) the metering of thecooling fluid flow into needle 26. Additional details on various aspectsof needle 26 along with alternative embodiments and principles ofoperation are disclosed in greater detail in U.S. Patent Publication No.2008/0154254 (Atty. Docket No. 000300US) entitled “Dermal andTransdermal Cryogenic Microprobe Systems and Methods,” the entirecontents of which are incorporated herein by reference. Previouslyincorporated U.S. Patent Publication No. 2008/0200910 (Attorney DocketNo. 025917-000500US) also discloses additional details on the needle 26along with various alternative embodiments and principles of operation.

The cooling fluid injected into lumen 38 of needle 26 will typicallycomprise liquid, though some gas may also be injected. At least some ofthe liquid vaporizes within needle 26, and the enthalpy of vaporizationcools the needle and also the surrounding tissue engaged by the needle.An optional heater 44 (illustrated in FIG. 1B) may be used to heat theproximal region of the needle in order to prevent unwanted skin damagein this area, as discussed in greater detail below. Controlling apressure of the gas/liquid mixture within needle 26 substantiallycontrols the temperature within lumen 38, and hence the treatmenttemperature range of the tissue. A relatively simple mechanical pressurerelief valve 46 may be used to control the pressure within the lumen ofthe needle, with the exemplary valve comprising a valve body such as aball bearing, urged against a valve seat by a biasing spring. Anexemplary relief valve is disclosed in U.S. Provisional PatentApplication No. 61/116,050 previously incorporated herein by reference.Thus, the relief valve may allow better temperature control in theneedle, minimizing transient temperatures. Further details on exhaustvolume are disclosed in previously incorporated U.S. Pat. Pub. No.2008/0200910.

The heater 44 may be thermally coupled to a thermally responsive element50, which is supplied with power by the controller 22 and thermallycoupled to a proximal portion of the needle 26. The thermally responsiveelement 50 can be a block constructed from a material of high thermalconductivity and low heat capacity, such as aluminum. A firsttemperature sensor 52 (e.g., thermistor, thermocouple) can also bethermally coupled the thermally responsive element 50 andcommunicatively coupled to the controller 22. A second temperaturesensor 53 can also be positioned near the heater 44, for example, suchthat the first temperature sensor 52 and second temperature sensor 53are placed in different positions within the thermally responsiveelement 50. In some embodiments, the second temperature sensor 53 isplaced closer to a tissue contacting surface than the first temperaturesensor 52 is placed in order to provide comparative data (e.g.,temperature differential) between the sensors 52, 53. The controller 22can be configured to receive temperature information of the thermallyresponsive element 50 via the temperature sensor 52 in order to providethe heater 44 with enough power to maintain the thermally responsiveelement 50 at a particular temperature.

The controller 22 can be further configured to monitor power draw fromthe heater 44 in order to characterize tissue type, perform devicediagnostics, and/or provide feedback for a tissue treatment algorithm.This can be advantageous over monitoring temperature alone, since powerdraw from the heater 44 can vary greatly while temperature of thethermally responsive element 50 remains relatively stable. For example,during treatment of target tissue, maintaining the thermally responsiveelement 50 at 40° C. during a cooling phase may take 1.0 W initially(for a needle <10 mm in length) and is normally expected to climb to 1.5W after 20 seconds, due to the needle 26 drawing in surrounding heat. Anindication that the heater is drawing 2.0 W after 20 seconds to maintain40° C. can indicate that an aspect of the system 10 is malfunctioningand/or that the needle 26 is incorrectly positioned. Correlations withpower draw and correlated device and/or tissue conditions can bedetermined experimentally to determine acceptable treatment powerranges.

In some embodiments, it may be preferable to limit frozen tissue that isnot at the treatment temperature, i.e., to limit the size of a formedcooling zone within tissue. Such cooling zones may be associated with aparticular physical reaction, such as the formation of an ice-ball, orwith a particular temperature profile or temperature volume gradientrequired to therapeutically affect the tissue therein. To achieve this,metering coolant flow could maintain a large thermal gradient at itsoutside edges. This may be particularly advantageous in applications forcreating an array of connected cooling zones (i.e., fence) in atreatment zone, as time would be provided for the treatment zone tofully develop within the fenced in portion of the tissue, while theouter boundaries maintained a relatively large thermal gradient due tothe repeated application and removal of refrigeration power. This couldprovide a mechanism within the body of tissue to thermally regulate thetreatment zone and could provide increased ability to modulate thetreatment zone at a prescribed distance from the surface of the skin. Arelated treatment algorithm could be predefined, or it could be inresponse to feedback from the tissue.

Such feedback could be temperature measurements from the needle 26, orthe temperature of the surface of the skin could be measured. However,in many cases monitoring temperature at the needle 26 is impractical dueto size constraints. To overcome this, operating performance of thesensorless needle 26 can be interpolated by measuring characteristics ofthermally coupled elements, such as the thermally responsive element 50.

Additional methods of monitoring cooling and maintaining an unfrozenportion of the needle include the addition of a heating element and/ormonitoring element into the needle itself. This could consist of a smallthermistor or thermocouple, and a wire that could provide resistiveheat. Other power sources could also be applied such as infrared light,radiofrequency heat, and ultrasound. These systems could also be appliedtogether dependent upon the control of the treatment zone desired.

Alternative methods to inhibit excessively low transient temperatures atthe beginning of a refrigeration cycle might be employed instead of ortogether with the limiting of the exhaust volume. For example, thesupply valve 32 might be cycled on and off, typically by controller 22,with a timing sequence that would limit the cooling fluid flowing sothat only vaporized gas reached the needle lumen 38 (or a sufficientlylimited amount of liquid to avoid excessive dropping of the needle lumentemperature). This cycling might be ended once the exhaust volumepressure was sufficient so that the refrigeration temperature would bewithin desired limits during steady state flow. Analytical models thatmay be used to estimate cooling flows are described in greater detail inpreviously incorporated U.S. Patent Pub. No. 2008/0154254.

FIG. 2B shows a cross-section of the housing 16. This embodiment of thehousing 16 may be powered by an external source, hence the attachedcable, but could alternatively include a portable power source. Asshown, the housing includes a cartridge holder 50. The cartridge holder50 includes a cartridge receiver 52, which may be configured to hold apressured refrigerant cartridge 18. The cartridge receiver 52 includesan elongated cylindrical passage 54, which is dimensioned to hold acommercially available cooling fluid cartridge 18. A distal portion ofthe cartridge receiver 52 includes a filter device 56, which has anelongated conical shape. In some embodiments, the cartridge holder 50may be largely integrated into the housing 16 as shown, however, inalternative embodiments, the cartridge holder 50 is a wholly separateassembly, which may be pre-provided with a coolant fluid source 18.

The filter device 56 may fluidly couple the coolant fluid source(cartridge) 18 at a proximal end to the valve 32 at a distal end. Thefilter device 56 may include at least one particulate filter 58. In theshown embodiment, a particulate filter 58 at each proximal and distalend of the filter device 56 may be included. The particulate filter 58can be configured to prevent particles of a certain size from passingthrough. For example, the particulate filter 58 can be constructed as amicroscreen having a plurality of passages less than 2 microns in width,and thus particles greater than 2 microns would not be able to pass.

The filter device 56 also includes a molecular filter 60 that isconfigured to capture fluid impurities. In some embodiments, themolecular filter 60 is a plurality of filter media (e.g., pellets,powder, particles) configured to trap molecules of a certain size. Forexample, the filter media can comprise molecular sieves having poresranging from 1-20 Å. In another example, the pores have an average sizeof 5 Å. The molecular filter 60 can have two modalities. In a firstmode, the molecular filter 60 will filter fluid impurities received fromthe cartridge 18. However, in another mode, the molecular filter 60 cancapture impurities within the valve 32 and fluid supply tube 36 when thesystem 10 is not in use, i.e., when the cartridge 18 is not fluidlyconnected to the valve 32.

Alternatively, the filter device 56 can be constructed primarily fromePTFE (such as a GORE material), sintered polyethylene (such as made byPOREX), or metal mesh. The pore size and filter thickness can beoptimized to minimize pressure drop while capturing the majority ofcontaminants. These various materials can be treated to make ithydrophobic (e.g., by a plasma treatment) and/or oleophobic so as torepel water or hydrocarbon contaminants.

It has been found that in some instances fluid impurities may leach outfrom various aspects of the system 10. These impurities can includetrapped moisture in the form of water molecules and chemical gasses. Thepresence of these impurities is believed to hamper cooling performanceof the system 10. The filter device 56 can act as a desiccant thatattracts and traps moisture within the system 10, as well as chemicalsout gassed from various aspects of the system 10. Alternately thevarious aspects of the system 10 can be coated or plated withimpermeable materials such as a metal.

As shown in FIG. 2B and in more detail in FIG. 2C and FIG. 2D, thecartridge 18 can be held by the cartridge receiver 52 such that thecartridge 18 remains intact and unpunctured. In this inactive mode, thecartridge may not be fluidly connected to the valve 32. A removablecartridge cover 62 can be attached to the cartridge receiver 52 suchthat the inactive mode is maintained while the cartridge is held by thesystem 10.

In use, the cartridge cover 62 can be removed and supplied with acartridge containing a cooling fluid. The cartridge cover 62 can then bereattached to the cartridge receiver 52 by turning the cartridge cover62 until female threads 64 of the cartridge cover 62 engage with malethreads of the cartridge receiver 52. The cartridge cover 62 can beturned until resilient force is felt from an elastic seal 66, as shownin FIG. 2C. To place the system 10 into use, the cartridge cover 62 canbe further turned until the distal tip of the cartridge 18 is puncturedby a puncture pin connector 68, as shown in FIG. 2D. Once the cartridge18 is punctured, cooling fluid may escape the cartridge by flowingthrough the filter device 56, where the impurities within the coolingfluid may be captured. The purified cooling fluid then passes to thevalve 32, and onto the coolant supply tube 36 to cool the probe 26. Insome embodiments the filter device, or portions thereof, may bereplaceable.

In some embodiments, the puncture pin connector 68 can have a two-wayvalve (e.g., ball/seat and spring) that is closed unless connected tothe cartridge. Alternately, pressure can be used to open the valve. Thevalve closes when the cartridge is removed. In some embodiments, theremay be a relief valve piloted by a spring which is balanced byhigh-pressure nitrous when the cartridge is installed and the system ispressurized, but allows the high-pressure cryogen to vent when thecryogen is removed. In addition, the design can include a vent port thatvents cold cryogen away from the cartridge port. Cold venting cryogenlocally can cause condensation in the form of liquid water to form fromthe surrounding environment. Liquid water or water vapor entering thesystem can hamper the cryogenic performance. Further, fluid carryingportions of the cartridge receiver 52 can be treated (e.g., plasmatreatment) to become hydrophobic and/or oleophobic so as to repel wateror hydrocarbon contaminants.

Turning now to FIG. 3A and FIG. 3B, an exemplary embodiment of probe 300having multiple needles 302 is described. In FIG. 3A, probe housing 316includes threads 306 that allow the probe to be threadably engaged withthe housing 16 of a cryogenic device. O-rings 308 fluidly seal the probehousing 316 with the device housing 16 and prevent coolant from leakingaround the interface between the two components. Probe 300 includes anarray of three distally extending needle shafts 302, each having asharpened, tissue penetrating tip 304. Using three linearly arrangedneedles allows a greater area of tissue to be treated as compared with asingle needle. In use, coolant flows through lumens 310 into the needleshafts 302 thereby cooling the needle shafts 302. Ideally, only thedistal portion of the needle shaft 302 would be cooled so that only thetarget tissue receives the cryogenic treatment. However, as the coolingfluid flows through the probe 300, probe temperature decreasesproximally along the length of the needle shafts 302 towards the probehub 318. The proximal portion of needle shaft 302 and the probe hub 318contact skin and may become very cold (e.g. −20° C. to −25° C.) and thiscan damage the skin in the form of blistering or loss of skinpigmentation. Therefore it would be desirable to ensure that theproximal portion of needle shaft 302 and hub 318 remains warmer than thedistal portion of needle shaft 302. A proposed solution to thischallenge is to include a heater element 314 that can heat the proximalportion of needle shaft 302 and an optional temperature sensor 312 tomonitor temperature in this region. To further this, a proximal portionof the needle shaft 302 can be coated with a highly thermally conductivematerial, e.g., gold, that is conductively coupled to both the needleshaft 302 and heater element 314. Details of this construction aredisclosed below.

In the exemplary embodiment of FIG. 3A, resistive heater element 314 isdisposed near the needle hub 318 and near a proximal region of needleshaft 302. The resistance of the heater element is preferably 1Ω to 1KΩ, and more preferably from 5Ω to 50Ω. Additionally, a temperaturesensor 312 such as a thermistor or thermocouple is also disposed in thesame vicinity. Thus, during a treatment as the needles cool down, theheater 314 may be turned on in order to heat the hub 318 and proximalregion of needle shaft 302, thereby preventing this portion of thedevice from cooling down as much as the remainder of the needle shaft302. The temperature sensor 312 may provide feedback to controller 22and a feedback loop can be used to control the heater 314. The coolingpower of the nitrous oxide may eventually overcome the effects of theheater, therefore the microprocessor may also be programmed with awarning light and/or an automatic shutoff time to stop the coolingtreatment before skin damage occurs. An added benefit of using such aheater element is the fact that the heat helps to moderate the flow ofcooling fluid into the needle shaft 302 helping to provide more uniformcoolant mass flow to the needles shaft 302 with more uniform coolingresulting.

The embodiment of FIG. 3A illustrates a heater fixed to the probe hub.In other embodiments, the heater may float, thereby ensuring proper skincontact and proper heat transfer to the skin. Examples of floatingheaters are disclosed in commonly assigned Int'l Pub. No. WO 2010/075448(Atty. Docket No. 002310PC) entitled “Skin Protection for SubdermalCryogenic Remodeling for Cosmetic and Other Treatments,” the entirety ofwhich is incorporated by reference herein.

In this exemplary embodiment, three needles are illustrated. One ofskill in the art will appreciate that a single needle may be used, aswell as two, four, five, six, or more needles may be used. When aplurality of needles are used, they may be arranged in any number ofpatterns. For example, a single linear array may be used, or a twodimensional or three dimensional array may be used. Examples of twodimensional arrays include any number of rows and columns of needles(e.g. a rectangular array, a square array, elliptical, circular,triangular, etc.), and examples of three dimensional arrays includethose where the needle tips are at different distances from the probehub, such as in an inverted pyramid shape.

FIG. 3B illustrates a cross-section of the needle shaft 302 of needleprobe 300. The needle shaft can be conductively coupled (e.g., welded,conductively bonded, press fit) to a conductive heater 314 to enableheat transfer therebetween. The needle shaft 302 is generally a small(e.g., 20-30 gauge) closed tip hollow needle, which can be between about0.2 mm and 15 cm, preferably having a length from about 0.3 cm to about1.5 cm. The conductive heater element 314 can be housed within aconductive block 315 of high thermally conductive material, such asaluminum and include an electrically insulated coating, such as Type IIIanodized coating to electrically insulate it without diminishing itsheat transfer properties. The conductive block 315 can be heated by aresister or other heating element (e.g. cartridge heater, nichrome wire,etc.) bonded thereto with a heat conductive adhesive, such as epoxy. Athermistor can be coupled to the conductive block 315 with heatconductive epoxy allows temperature monitoring. Other temperaturesensors may also be used, such as a thermocouple.

A cladding 320 of conductive material is directly conductively coupledto the proximal portion of the shaft of the needle 302, which can bestainless steel. In some embodiments, the cladding 320 is a layer ofgold, or alloys thereof, coated on the exterior of the proximal portionof the needle shaft 302. In some embodiments, the exposed length ofcladding 320 on the proximal portion of the needle is 2-100 mm. In someembodiments, the cladding 320 can be of a thickness such that the cladportion has a diameter ranging from 0.017-0.020 in., and in someembodiments 0.0182 in. Accordingly, the cladding 320 can be conductivelycoupled to the material of the needle 302, which can be less conductive,than the cladding 320. The cladding 320 may modify the lateral forcerequired to deflect or bend the needle 26. Cladding 320 may be used toprovide a stiffer needle shaft along the proximal end in order to moreeasily transfer force to the leading tip during placement and allow thedistal portion of the needle to deflect more easily when it isdissecting a tissue interface within the body. The stiffness of needle26 can vary from one end to the other end by other means such asmaterial selection, metal tempering, variation of the inner diameter ofthe needle 26, or segments of needle shaft joined together end-to-end toform one contiguous needle 26. In some embodiments, increasing thestiffness of the distal portion of the needle 26 can be used to flex theproximal portion of the needle to access difficult treatment sites as inthe case of occipital neuralgia where bending of the needle outside thebody may be used to access a target peripheral nerve along the desiredtissue plane.

In some embodiments, the cladding 320 can include sub-coatings (e.g.,nickel) that promote adhesion of an outer coating that would otherwisenot bond well to the needle shaft 302. Other highly conductive materialscan be used as well, such as copper, silver, aluminum, and alloysthereof. In some embodiments, a protective polymer or metal coating cancover the cladding to promote biocompatibility of an otherwisenon-biocompatible but highly conductive cladding material. Such abiocompatible coating however, would be applied to not disruptconductivity between the conductive block 315. In some embodiments, aninsulating layer, such as a ceramic material, is coated over thecladding 320, which remains conductively coupled to the needle shaft302.

FIGS. 3C and 3D illustrates a detachable probe tip 322 having a hubconnector 324 and an elongated probe 326. The probe tip 322 shares muchof its construction with probe 300. However, the elongated probe 326features a blunt tip 328 that is adapted for blunt dissection of tissue.The blunt tip 328 can feature a full radius tip, less than a full radiustip, or conical tip. In some embodiments, a dulled or truncated needleis used. The elongated probe 326 can be greater than 20 gauge in size,and in some embodiments range in size from 25-30 gauge. As with theembodiments described above, an internal supply tube 330 extends incantilever. However, the exit of the supply tube 330 can be disposed atpositions within the elongated probe 326 other than proximate the blunttip 328. Further, the supply tube 330 can be adapted to create anelongated zone of cooling, e.g., by having multiple exit points forcryofluid to exit from.

The elongated probe 326 and supply tube 330 may be configured toresiliently bend in use, throughout their length at angles approaching120°, with a 5-10 mm bend radius. This may be very challengingconsidering the small sizes of the elongated probe 326 and supply tube330, and also considering that the supply tube 330 is often constructedfrom fused silica. Accordingly, the elongated probe 326 can beconstructed from a resilient material, such as stainless steel, and of aparticular diameter and wall thickness [0.004 to 1.0 mm], such that theelongated probe in combination with the supply tube 330 is not overlyresilient so as to overtly resist manipulation, but sufficiently strongso as to prevent kinking that can result in coolant escaping. Forexample, the elongated probe can be 15 gauge or smaller in diameter,even ranging from 20-30 gauge in diameter. The elongated probe can havea very disparate length to diameter ratio, for example, the elongatedprobe can be greater than 30 mm in length, and in some cases range from30-100 mm in length. To further the aforementioned goals, the supplytube 330 can include a polymer coating 332, such as a polyimide coatingthat terminates approximately halfway down its length, to resist kinkingand aid in resiliency. The polymer coating 332 can be a secondarycoating over a primary polyimide coating that extends fully along thesupply tube. However, it should be understood that the coating is notlimited to polyimide, and other suitable materials can be used. In someembodiments, the flexibility of the elongated probe 326 will vary fromthe proximal end to the distal end. For example, by creating certainportions that have more or less flexibility than others. This may bedone, for example, by modifying wall thickness, adding material (such asthe cladding discussed above), and/or heat treating certain portions ofthe elongated probe 326 and/or supply tube 330. For example, decreasingthe flexibility of elongated probe 326 along the proximal end canimprove the transfer of force from the hand piece to the elongated probeend for better feel and easier tip placement for treatment. Theelongated probe and supply line 330 are may be configured to resilientlybend in use to different degrees along the length at angles approaching120°, with a varying bend radius as small as 5 mm. In some embodiments,the elongated probe 326 will have external markings along the needleshaft indicating the length of needle inserted into the tissue.

An exemplary algorithm 400 for controlling the heater element 314, andthus for transferring heat to the cladding 320, is illustrated in FIG.4A. In FIG. 4A, the start of the interrupt service routine (ISR) 402begins with reading the current needle hub temperature 404 using atemperature sensor such as a thermistor or thermocouple disposed nearthe needle hub. The time of the measurement is also recorded. This datais fed back to controller 22 where the slope of a line connecting twopoints is calculated. The first point in the line is defined by thecurrent needle hub temperature and time of its measurement and thesecond point consists of a previous needle hub temperature measurementand its time of measurement. Once the slope of the needle hubtemperature curve has been calculated 406, it is also stored 408 alongwith the time and temperature data. The needle hub temperature slope isthen compared with a slope threshold value 410. If the needle hubtemperature slope is less than the threshold value then a treating flagis activated 412 and the treatment start time is noted and stored 414.If the needle hub slope is greater than or equal to the slope thresholdvalue 410, an optional secondary check 416 may be used to verify thatcooling has not been initiated. In step 416, absolute needle hubtemperature is compared to a temperature threshold. If the hubtemperature is less than the temperature threshold, then the treatingflag is activated 412 and the treatment start time is recorded 414 aspreviously described. As an alternative, the shape of the slope could becompared to a norm, and an error flag could be activated for an out ofnorm condition. Such a condition could indicate the system was notheating or cooling sufficiently. The error flag could trigger anautomatic stop to the treatment with an error indicator light.Identifying the potential error condition and possibly stopping thetreatment may prevent damage to the proximal tissue in the form of toomuch heat, or too much cooling to the tissue. The algorithm preferablyuses the slope comparison as the trigger to activate the treatment flagbecause it is more sensitive to cooling conditions when the cryogenicdevice is being used rather than simply measuring absolute temperature.For example, a needle probe exposed to a cold environment wouldgradually cool the needle down and this could trigger the heater to turnon even though no cryogenic cooling treatment was being conducted. Theslope more accurately captures rapid decreases in needle temperature asare typically seen during cryogenic treatments.

When the treatment flag is activated 418 the needle heater is enabled420 and heater power may be adjusted based on the elapsed treatment timeand current needle hub temperature 422. Thus, if more heat is required,power is increased and if less heat is required, power is decreased.Whether the treatment flag is activated or not, as an additional safetymechanism, treatment duration may be used to control the heater element424. As mentioned above, eventually, cryogenic cooling of the needlewill overcome the effects of the heater element. In that case, it wouldbe desirable to discontinue the cooling treatment so that the proximalregion of the probe does not become too cold and cause skin damage.Therefore, treatment duration is compared to a duration threshold valuein step 424. If treatment duration exceeds the duration threshold thenthe treatment flag is cleared or deactivated 426 and the needle heateris deactivated 428. If the duration has not exceeded the durationthreshold 424 then the interrupt service routine ends 430. The algorithmthen begins again from the start step 402. This process continues aslong as the cryogenic device is turned on.

Preferred ranges for the slope threshold value may range from about −5°C. per second to about −90° C. per second and more preferably range fromabout −30° C. per second to about −57° C. per second. Preferred rangesfor the temperature threshold value may range from about 15° C. to about0° C., and more preferably may range from about 0° C. to about 10° C.Treatment duration threshold may range from about 15 seconds to about 75seconds.

It should be appreciated that the specific steps illustrated in FIG. 4Aprovide a particular method of heating a cryogenic probe, according toan embodiment of the present invention. Other sequences of steps mayalso be performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated in FIG. 13 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications.

The heating algorithm may be combined with a method for treating apatient. Referring now to FIG. 4B, a method 100 facilitates treating apatient using a cryogenic cooling system having a reusable or disposablehandpiece either of which that can be self-contained or externallypowered with replaceable needles such as those of FIG. 1B and a limitedcapacity battery or metered electrical supply. Method 100 generallybegins with a determination 110 of the desired tissue therapy andresults, such as the inhibition of pain from a particular site.Appropriate target tissues for treatment are identified 112 (a tissuethat transmits the pain signal), allowing a target treatment depth,target treatment temperature profile, or the like to be determined. Step112 may include performing a tissue characterization and/or devicediagnostic algorithm, based on power draw of system 10, for example.

The application of the treatment algorithm 114 may include the controlof multiple parameters such as temperature, time, cycling, pulsing, andramp rates for cooling or thawing of treatment areas. In parallel withthe treatment algorithm 114, one or more power monitoring algorithms 115can be implemented. An appropriate needle assembly can then be mounted116 to the handpiece, with the needle assembly optionally having aneedle length, skin surface cooling chamber, needle array, and/or othercomponents suitable for treatment of the target tissues. Simpler systemsmay include only a single needle type, and/or a first needle assemblymounted to the handpiece.

Pressure, heating, cooling, or combinations thereof may be applied 118to the skin surface adjacent the needle insertion site before, during,and/or after insertion 120 and cryogenic cooling 122 of the needle andassociated target tissue. Non-target tissue directly above the targettissue can be protected by directly conducting energy in the form ofheat to the cladding on a proximal portion of the needle shaft duringcooling. Upon completion of the cryogenic cooling phase the needles willneed additional “thaw” time 123 to thaw from the internally createdcooling zone to allow for safe removal of the probe without physicaldisruption of the target tissues, which may include, but not be limitedto nerves, muscles, blood vessels, or connective tissues. This thaw timecan either be timed with the refrigerant valve shut-off for as short atime as possible, preferably under 15 seconds, more preferably under 5seconds, manually or programmed into the controller to automaticallyshut-off the valve and then pause for a chosen time interval until thereis an audible or visual notification of treatment completion.

Heating of the needle may be used to prevent unwanted skin damage usingthe apparatus and methods previously described. The needle can then beretracted 124 from the target tissue. If the treatment is not complete126 and the needle is not yet dull 128, pressure and/or cooling can beapplied to the next needle insertion location site 118, and theadditional target tissue treated. However, as small gauge needles maydull after being inserted only a few times into the skin, any needlesthat are dulled (or otherwise determined to be sufficiently used towarrant replacement, regardless of whether it is after a singleinsertion, 5 insertions, or the like) during the treatment may bereplaced with a new needle 116 before the next application ofpressure/cooling 118, needle insertion 120, and/or the like. Once thetarget tissues have been completely treated, or once the cooling supplycanister included in the self-contained handpiece is depleted, the usedcanister and/or needles can be disposed of 130. The handpiece mayoptionally be discarded.

As shown at FIG. 5, the greater occipital nerve (GON) is a spinal nerve,specifically the medial branch of the dorsal primary ramus of cervicalspinal nerve. This nerve arises from between the first and secondcervical vertebrae, along with the lesser occipital nerve. It ascendsafter emerging from the suboccipital triangle obliquely between theinferior oblique and semispinalis capitis muscle. It then passes throughthe semispinalis capitis muscle and ascends to innervate the skin alongthe posterior part of the scalp to the vertex. It innervates the scalpat the top of the head, over the ear and over the parotid glands. Afteremerging from the suboccipital triangle obliquely between the inferioroblique and semispinalis capitis muscle, the GON then passes through thefascia of the trapezius muscle and pierces the semispinalis capitismuscle to ascend to innervate the skin along the posterior part of thescalp to the vertex. It innervates the scalp at the top of the head,over the ear and over the parotid glands.

The GON may be treated using the systems disclosed herein by creating acooling zone at a GON block site The GON block site is normally selectedbased on: Arterial palpation; use of a Doppler flow probe, and sensorynerve stimulation. In addition, ultrasound visualization can be used toidentify the nerve and recognition of anatomical variability in itscourse, division and relationship to surrounding structures. It is moredifficult to visualize the GON at the Superior Nuchal Line due toshallow depth and smaller diameter.

FIG. 6 shows a typical GON block site 1. The GON block site 1 is shownat the superior Nuchal Line. Based on GON depth of ˜8 mm, devices asshort as 6 mm can be used to access the Gon block site 1. The GONdiameter at GON block site 1 is approximately 4.2 mm in diameter. TheGON may have several branches at GON block site 1. Here, the GON isnormally located ˜3.8 cm (1.5-7.5 cm) from the midline at a horizontallevel between the external occipital protuberance and the mastoidprocess. The Gon block site 1 is normally identified by palpation ornerve stimulation, as the occipitalis muscle, splenius capitis muscle,and the trapezius muscle all attach at this line. The location of theGON for anesthesia or any other neurosurgical procedure has beenestablished as approximately 2 cm lateral to the external occipitalprotuberance, and approximately 2 cm inferior.

An alternative GON block site 2 is shown as well. Based on the GON depthat GON block site 2, the nerve is likely too deep here for devices lessthan 12 mm. The nerve depth is approximately 17 mm. The GON diameter atGON block site 1 is approximately 4.8 mm in diameter. The GON block site2 is relatively proximal to the superior nuchal line, at C2, superficialto the obliquus capitis inferior muscle. Since the GON block site 2 isrelatively close to the vertebral artery, the procedure here should notbe performed without ultrasound guidance.

FIG. 7 shows the location of the lesser occipital nerve (LON), which canalso be treated using the systems disclosed herein. The LON arises fromthe lateral branch of the ventral ramus of the second cervical nerve,sometimes also from the third. This LON branch is occasionally derivedfrom the GON. The LON curves around and ascends along the posteriorborder of the sternocleidomastoid. Near the cranium the LON perforatesthe deep fascia, and continues upward along the side of the head behindthe auricula. The LON provides an auricular branch. Often, the LONvaries in size, and is sometimes duplicated. The LON supplies the skinof the upper and back part of the auricula, communicating with themastoid branch of the great auricular. The LON also supplies the skinand communicates with the GON, the great auricular, and the posteriorauricular branch of the facial.

FIG. 8 shows a schematic illustration of the courses of the greater andlesser occipital nerves. The GON pierces the semispinalis capitis muscleand then travels in a superolateral direction. At the level of theoccipital protuberance, the GON is approximately 3-4 cm lateral to themidline, and the greater and lesser occipital nerves are actually closeto each other. The LON follows the posteromedial border of thesternocleidomastoid muscle and only crosses it after it has traveledsuperiorly.

FIG. 9 shows a schematic illustration of GON and LON treatmentlocations, illustrated by tips of the cannulas. The occipital nerveemergences 3 cm below 1.5 cm lateral from the occipital protuberance. AGON treatment location (left most) is shown above superior nuchal line,2.5-3.0 cm lateral to external occipital protuberance, and 6-8 mm belowskin. This location is medial to occipital artery, which is typically areliable landmark for most patients. The GON treatment location is alsopalpable. A LON treatment location (right most) is located 2.5 cmlateral to the artery.

Methods can be implemented using one or more aspects of the systemdisclosed above for treatment of occipital neuralgia. Generally, atleast one needle of a needle probe is placed proximate to the occipitalnerve. The needle probe can include more needles, however only one isrequired. A treatment algorithm is then enacted to provide the needlewith cooling fluid for a predetermined amount of time. Further, warmingphases may take place before and after the cooling fluid is provided,however, the warming phases are not required for efficacy of treatment.

The treatment algorithm is configured to provide coolant long enough toremodel tissue of the occipital nerve and thereby mitigate symptoms ofoccipital neuralgia.

Needle probes for treating symptoms of occipital neuralgia areconfigured to access relatively deep locations within tissue to treatdeeper nerves require longer needles. Longer needles of a multi-needleneedle probe may also require a smaller gauge (larger diameter) so thateach needles has sufficient rigidity to maintain consistent spacing whenplaced deep in the tissue, but not so large as to create significantmechanical injury to the skin and tissue when inserted (e.g. larger than20 ga). Alternate configurations of the needle probe have 2 or moreneedles spaced generally 3-7 mm apart of lengths ranging up to 20 mm orgreater, typically of 25 gauge or 23 gauge. Single needle configurationscan be even longer and may require active nerve location such asultrasound or electrical nerve stimulation to guide placement of theneedle. A long, single needle does not require the skin protectionelements of the (e.g. active heating of the skin warmer and/or cladding)found in the shorter needle as the cooling zone can be placedsufficiently deep below the dermis to prevent injury.

Devices used for the treatment of symptoms of occipital neuralgia wereconfigured with 3 needles each of 27 gauge, 6 mm length, and 2 mmspacing between needles. Although this configuration was effective insome cases, it is believe that a different design may be more effectiveand/or be easier to use. Where the GON is generally larger in diameterthan the LON and is found deeper below the dermis, a cryoprobe withlonger needles and a wider spacing between needles is preferable. Aneedle probe may include needles placed 5-8 mm apart and 12 mm in lengthor greater, which would more effectively treat the GON. Additionally theGON and other nerves become more superficial and smaller in diameter asit travels in the inferior direction, thus a cryoprobe can be optimizedfor the treatment of a nerve in both length and needle spacing dependingon the nerve and treatment location. With increased spacing, systemmodifications may be required to increase cooling power to ensure thatthe target temperature is reached between adjacent needles to achievecreation of a preferred cooling zone volume, also referred to herein asa cryozone. For example, in some embodiments, devices and treatmentcycles may be configured to generate cryozones (defined by a 0 degreeisotherm) having a cross-sectional area of approximately 14-55 mm²(e.g., 27 mm²). Optionally, the devices and treatment cycles may beconfigured to generate cryozones having a volume of approximately 65-125mm³ (e.g., 85 mm³). This could be done by increasing the flow rate ofthe cryogen or by changing to a cryogen with more cooling power. Powerto the heater can also be decreased, minimized, or eliminated, since thelocation is not generally associated with aesthetics, thus, allowingwider spacing between needles.

Variability from patient to patient in the depth of the occipital nervecreated challenges with early treatments. Using PENS to determine theapproximate location and depth of the nerve and then by placing a 12 mmneedle probe to that approximate location and depth, either by partiallyinserting it or by compressing the tissue (by pressing hard), the PENSguided treatments were generally more successful.

A single needle probe configuration (e.g. 1×90 mm) can also be used,optionally with the help of ultrasound nerve location or percutaneouselectrical nerve stimulation (PENS) to place the single needle adjacentto one side of the nerve. This configuration would be helpful fortreating nerves that are very deep, i.e., greater than 15 mm below thedermis. Larger sized occipital nerves may require treatment from bothsides to make sure that the cold zone created by the needle fully coversthe nerve. Adjacent treatments placing a needle to either side of thenerve during two successive treatment cycles will still provide aneffective treatment of the entire occipital nerve cross-section.

Other variations are within the spirit of the present disclosure. Thus,while the invention is susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in the drawings and have been described above in detail. It shouldbe understood, however, that there is no intention to limit theinvention to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the invention, asdefined in the appended claims.

1. A system for alleviating occipital neuralgia, the system comprising:a needle probe comprising a pair of needles, each of the needles havinga proximal end, a distal end, and a needle lumen therebetween, theneedles configured for insertion proximate to a location of an occipitalnerve, the needles being spaced apart to flank at least a portion of theoccipital nerve; a cooling fluid supply lumen extending distally withineach of the needle lumens to a distal portion of the needle lumens; acooling fluid source couplable to the cooling fluid supply lumens todirect cooling fluid flow into the needle lumens; and a controllerhaving at least one processor configured to implement an occipitalneuralgia treatment algorithm for controlling the cooling fluid sourceso that liquid from the cooling flow vaporizes within the needle lumensto provide a treatment cycle to the location of the occipital nerve suchthat the occipital neuralgia is mitigated.
 2. The system of claim 1,further comprising: a heating element coupled with the proximal ends ofthe needles, the heating element configured to deliver heating phases toskin of the patient; and wherein the processor is configured to controlthe cooling fluid flow and the heating element in response to operatorinput, the processor configured to provide the treatment cycle inresponse to the operator input, the treatment cycle comprising at leastone heating phase and one cooling phase.
 3. The system of claim 1,wherein the occipital neuralgia treatment algorithm is configured tocause the needle probe to generate a cryozone having a volume of 65-125mm³.
 4. The system of claim 1, wherein the pair of needles are spacedapart 2-8 mm to flank the portion of the occipital nerve.
 5. The systemof claim 4, wherein the pair of needles are spaced apart 2 mm to flankthe portion of the occipital nerve.
 6. The system of claim 1, whereinthe pair of needles have a length in a range of 3 mm to 15 mm.
 7. Thesystem of claim 1, wherein the location of the occipital nerve comprisesa greater occipital nerve.
 8. The system of claim 1, wherein thelocation of the occipital nerve comprises a lower occipital nerve.